A correction information calculating device calculates correction information representing correspondence relationship between a position of a pixel in an image projected onto a projection surface by projectors including an image forming element and a position of a pixel of the image forming element. The correction information calculating device includes a supply unit that supplies first and second measurement image data representing a first and second measurement pattern including a plurality of characteristic diagrams that define characteristic points to a first and second projector that projects an image onto a first and second projection area on the projection surface and a calculation unit that calculates the correction information by comparing positions of the plurality of characteristic points in a photographed pattern acquired by photographing the first and second measurement patterns.